Hop is a moraceous perennial plant (scientific name: Humulus lupulus) native to Europe, and a berry cone (ripe female flower) of the same is generally called as hop and well known by reason of use for imparting bitterness and aroma to beer, and has been ingested for many years. The bitterness and aroma are originated from a lupulin part of a hop (a yellow granule formed at a root of an inner glume of a berry cone). A hop has been also used as a folk medicine, and as the effects a tranquilizing effect, a quick and sound sleep effect, an appetite stimulation, a stomachic action, a diuretic action, and an antidiabetic action are reported in Japanese Unexamined Patent Application Publication No. S50-70512 (Patent Literature 1), and Japanese Unexamined Patent Application Publication No. S59-59623 (Patent Literature 2).
Recently, with respect to polyphenols originated from a hop glume, which is a hop berry cone excluding a lupulin part, a lipase inhibitory action, a body weight increase suppression action, etc. are reported in Japanese Unexamined Patent Application Publication No. 2001-321166 (Patent Literature 3), Japanese Unexamined Patent Application Publication No. 2001-131080 (Patent Literature 4), etc. As described above, a hop has a variety of health-related functions, on the other hand a hop contains a large number of bittering components, such as α acids and iso-α acids as represented by humulones and isohumulones, and is very difficult to be ingested pleasantly.
Japanese Unexamined Patent Application Publication No. 2008-212041 (Patent Literature 5) has reported that α acids, iso-α acids, etc. can be oxidatively decomposed by oxidatively ripening a hop, so that bitterness can be mitigated.
Meanwhile, many kinds of pleasure beverages filled in a container, such as a can, and a PET bottle, have been developed recently, and also commercially supplied. It is important to impart a flavor which creates a feeling of briskness, richness, luxuriousness, etc. to a pleasure beverage, in order to stimulate consumption. However, if an additive for imparting a flavor is added to a beverage, the original taste of the beverage is impaired frequently. Therefore, methods for imparting a favorable flavor to a beverage without impairing the taste of the beverage have been heretofore investigated.
For example, Japanese Unexamined Patent Application Publication No. 2010-268774 (Patent Literature 6) describes that powders of a water extract of roasted barley and/or adlay, and a water extract of a herb are added to a beverage in order to improve the palatability by improving an unpleasant aftertaste of a beverage containing barley tea filled in a container without impairing the original taste of the beverage containing barley tea.
Further, Japanese Unexamined Patent Application Publication No. 2008-136367 (Patent Literature 7) describes that a tea drink having an excellent flavor suppressing an odor, bitterness, and astringency derived from polyphenols can be provided by adding an extract component of tea leaves including roasted tea leaves, and α-cyclodextrin to a tea drink containing polyphenols at a high concentration, owing to a synergistic effect of a roast aroma of roasted tea and a masking action of α-cyclodextrin.
A hop is sometimes utilized for imparting a good quality taste and aroma as in the case of beer. Japanese Unexamined Patent Application Publication No. 2011-83266 (Patent Literature 8) reports that hop tea was produced using branches and leaves, berry cones, etc. of a hop as source materials. However, because of a unique intensive bitterness, when a hop is added to a beverage such as tea with only limited original bitterness, the taste is impaired.
As described above, in the case of a beverage type which undergoes a wort boiling step or a low temperature ripening step purposed to remove an unpleasant odor (off-flavor), the unpleasant odor can be removed, however, when a hop was utilized in a beverage such as a soft drink, like tea or soda, which does not undergo a step for removing an off-flavor in the production method, the original taste of the beverage was impaired.